Add models and routes for costs, consumption, equipment, maintenance, and production; implement CRUD operations and unit tests

models/maintenance.py

@@ -0,0 +1,17 @@
+from sqlalchemy import Column, Integer, String, DateTime, ForeignKey, func
+from sqlalchemy.orm import relationship
+from config.database import Base
+
+
+class Maintenance(Base):
+    __tablename__ = "maintenance"
+
+    id = Column(Integer, primary_key=True, index=True)
+    scenario_id = Column(Integer, ForeignKey("scenario.id"), nullable=False)
+    performed_at = Column(DateTime(timezone=True), server_default=func.now())
+    details = Column(String, nullable=True)
+
+    scenario = relationship("Scenario", back_populates="maintenance_items")
+
+    def __repr__(self):
+        return f"<Maintenance id={self.id} scenario_id={self.scenario_id} performed_at={self.performed_at}>"